Dynamic mechanical and solid-state 13 C nuclear magnetic resonance (NMR) analyses have been used to assess a molecular-scale heterogeneity in a raw elastomer (butadiene-acrylonitrile copolymer elastomer, NBR), a microcrystalline polymer (poly(vinyl chloride), PVC), and their 50/50 blend. The presenc
WIM/WISE NMR Studies of Chain Dynamics in Solid Polymers and Blends
✍ Scribed by Xiaohua Qiu; Peter A Mirau
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 82 KB
- Volume
- 142
- Category
- Article
- ISSN
- 1090-7807
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✦ Synopsis
Wideline separation (WISE) NMR with windowless isotropic mixing (WIM) is developed as a method to study the dynamics of polymers and blends. This experiment is designed to measure the dynamics of polymers through the proton lineshapes that are correlated with the carbon chemical shifts in two-dimensional NMR experiments. If the atoms experience large amplitude fluctuations that are fast compared to the dipolar broadening, then the proton lines will be narrowed relative to rigid solids. We have modified the WISE experiment by replacing the cross polarization step with WIM to quench spin diffusion during the cross polarization so that the proton linewidths can be directly related to the chain dynamics. Two-dimensional WIM/WISE has been used to measure the main-chain and side-chain dynamics in poly(n-butyl methacrylate) and blends of polystyrene and poly(vinyl methyl ether).
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